Method and an arrangement for controlling the tensioning force in an advancing yarn

ABSTRACT

An advancing yarn passes through yarn retardation means and pneumatic yarn tension sensing means. A stream of pressurized medium is directed against the yarn deflecting the same and suffering as a result of said deflection a pressure drop which is transmitted to actuation means which adjust the retardation force exerted by the retardation means upon the advancing yarn, so as to maintain the yarn tension on a preselected level. There are also provided means for automatic shut-off of the yarn advancing means in case of yarn breakage.

United States Patent 1191 Stritzko June 25, 1974 METHOD AND AN ARRANGEMENT FOR 3,512,692 /1970 Horton 2215 39 CONTROLLING THE TENSIQNING FORCE 18/1338 go otgertetlal. .5712115:

, e1 e a 2. IN AN ADVANCING YARN 3,558,026 1/1971 Rosen 226/39 [75] Inventor: Vilem Stritzko, Strengelbach, 3,672,588 6/1972 Bensa 242/ Switzerland [73] Assignee: Bleiche AG, Zoffingen, Switzerland Primary ExaminerAllen N. Knowles [22] Filed: May 10, 1973 Attorney, Agent, or FirmMichael S. Striker [21] Appl. No.: 359,029

- [57] ABSTRACT [30] Foreign Applwauon Pnomy Data An advancing yarn passes through yarn retardation May 15, 1972 Switzerland 7199/72 means and pneumatic yam tension sensing means A stream of pressurized medium is directed against the [52] US. Cl 226/39, 226/1], 226/195, yam deflecting the Same and Suffering as a result of 226/100 242/150 242/147 242/148 said deflection a pressure drop which is transmitted to [51] Int. Cl Bh 23/1S actuation means which adjust the retardation force [58] Fleld of Search 226/38 erted by the retardation means upon the advancing 242/45 147 147 1561 yarn, so as to maintain the yarn tension on a prese- 148 lected level. There are also provided means for automatic shut-off of the am advancin means in case of [56] References Cited yam breakage y g UNITED STATES PATENTS 3,385,491 5/1968 Helms 226/39 X 8 Claims, 5 Drawing Figures ll 16 2 l2 20 I (I I 1 I I 1 I 1 -I in 1 l l o 9 s g u. 18 g 7 A 1. l z fi 8 1 +1 PATENTEBJUNZS m4 SHEET 1 BF 2 METHOD AND AN ARRANGEMENT FOR CONTROLLING THE TENSIONING FORCE IN AN ADVANCING YARN BACKGROUND OF THE INVENTION The present invention relates to a method and an apparatus for controlling the tensioning force in an advancing yarn, particularly for use in the textile industry, more particularly in a machine in which the advancing yarn is being retarded by retardation means.

There are already known in the textile industry various devices for retardation of the advancing yarn in order to establish tension therein. However, these con-.

ventional devices are disadvantageous in that they either do not control the tension in the yarn at all or only to an insufficient extent, or that they have a complicated and, consequently, expensive construction.

BRIEF SUMMARY OF THE INVENTION It is an object of the present invention to avoid the drawbacks of the prior art.

It is a particular object of the invention to devise a method of controlling the tension in the advancing yarn, which is both simple and reliable.

It is still another object of the invention to provide an apparatus for accomplishing the method, which is uncomplicated, inexpensive and which does not interfere with the production.

Yet another object of the invention is provision of an apparatus for counteracting the instantaneous variations in the yarn tension from a selected value so as to maintain the tension at a substantially constant level.

It is a further object of the invention to provide an apparatus in which the selected tension and the response to the deviations from the same can be adjusted.

It is another object of the invention to provide a device for automatic shut-down of the yarn advancement means in case of yarn breakage.

In pursuance of these objects and others which will become apparent hereinafter, one feature of the invention resides in directing a stream of pressurized medium, particularly air, against the advancing yarn which is supported by two abutments so as to be free to deflect from its original, straight-line position, the amount of deflection being a function of the instantaneous tension in the yarn. The instantaneous pressure in the vicinity of the stream, which is a function of the yarn deflection and, consequently, its tension, is transmitted to, and influences, the yarn retardation means in such a manner as to counteract the deviations of the yarn tension from the selected value. Another feature of the present invention is an apparatus for accomplishing this method, comprising sensing means whose walls, together with the advancing yarn itself which is supported between the abutments, define a confined space into which pressurized medium is supplied via a jet nozzle so as to be directed against the advancing yarn and to deflect the same as a function of the pressure in the confined space which in turn depends on the tension in the advancing yarn; connecting means which communicate with said confined space through a bore situated in vicinity of the jet nozzle; and yarn retardation means comprising a pneumatic amplifier communicating with the connection means so that the pressure in the amplifier corresponds to the pressure in the confined space of the sensing means, wherein said amplifier displaces a spring-biased displaceable yarn retardation disc in relation to a stationary yarn retardation disc so as to apply variable force to the advancing yarn passing between these two discs and being retarded by the same as a function of the pressure variation so as to counteract the variations in the yarn tension.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a front elevational view of an embodiment of a device according to the invention, shown partially in cross-section in the area of the jet nozzle;

FIG. 2 is a cross-sectional view taken along the line Il-II of FIG. 1 with some portions being broken away;

FIG. 3 is a top plan view of the embodiment shown in FIG. 1 in a partial cross-section;

FIG. 4 is a partial cross-sectional lateral view taken along the line IV-IV in FIG. 1, on an enlarged scale; and

FIG. 5 is a top plan view of another embodiment of the amplifier shown in FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS:

Discussing now the drawing in detail, FIGS. 1 to 4 show a sensing device comprising a support plate 1, a spacer 3, and a cover plate 4 which are joined together by screws 2. The support plate 1, cover plate 4 and spacer 3 define a groove 5 having a rectangular wall 6 whose dimensions are given by the spacer 3. It is to be noted that the spacer 3 can easily be exchanged so as to adjust the distance between the support plate 1 and the cover plate 4. The support plate 1 is provided with two grooves 7 and 8, and abutment members 9 and 10 are inserted into the-same. A jet nozzle 11 is provided between the abutments 9 and 10, communicating with the groove 5 on one side and with pressurized medium source, which is not illustrated, via a bore 12 and a conduit 13. A further bore 14 is provided in the support plate 1, which is spaced from the jet nozzle 11 and which communicates with the groove 5 on one end, and via a conduit 15 with a pneumatic amplifier 16, on the other end. The cover plate is transparent and is provided with markings 17 indicating the tension force in an advancing yarn.

The support plate I is rigidly connected to an angular member 19 which, in turn, is attached to a bracket 20. The bracket 20 is attached to a support 22 by means of screws 21. The stationary support 22 also accommodates an eyelet 23 serving for guidance of an advancing yarn 18.

Having described the sensing means, reference will now be had to yarn retardation means, particularly as illustrated in FIG. 3. A threaded shaft 24 of a pivot 25 is accommodated in a bore of the support 22, and a portion 26 of a housing 41 of the amplifier 16 is threaded onto the same so as to establish, in cooperation with a support disc 27 and a shoulder of the pivot 25, a firm attachment of the pivot 25 and the housing 41 to the support 22. An annular disc 28 is arranged adjacent the support disc 27 so as to abut against the same when subjected to forces acting in the axial direction of the pivot 25. Two retarding discs 29 and 30 are supported for free rotation on the pivot 25. The pivot 25 is provided with two axial bores 31 and 32, and its free end is bifurcated by two slots 33 and 34. An adjusting screw 36 is threaded into the female thread 35 of the bore 31. A compression spring 38 surrounding the pivot 25 is accommodated between the adjusting screw 36 and a disc 37 which is provided with a diametn'c guide rib 39 and is accommodated on the pivot 25 in such a manner that the diametric rib 39 extends through the slots 33 and 34 so as to prevent the disc 37 from turning. When the biasing force in the spring 38 is adjusted by the adjusting screw 36, the disc 38 abuts against the rotatable disc 30 forcing the same against the rotatable disc 29 so as to vary the retardation force exerted by the discs 39 and 30 on the advancing yarn 18 passing between the same.

A driving rod 40 is attached on one of its ends to the diarnetral guide rib 39, being accommodated in the bore 32 so as to be displaceable in the axial direction of the pivot 25, and abutting at its other end against a diaphragm 42 which air-tightly divides the inner space of the housing 41 of the pneumatic amplifier 16 in a pressure chamber 43 and an equalizing chamber 44. The pressure chamber 43 communicates with the bore 14 via the conduit 15. The diaphragm 42 is supported in a mount 45 and is made of an elastic material, so that when the pressure in the pressure chamber 43 increases, the diaphragm 42 is elastically deformed, simultaneously displacing the driving rod 40 in the axial direction of the pivot 25 and toward the adjusting screw 36 against the biasing force of the spring 38, whereby the retardation force exerted on the advancing yarn 18 by the retarding discs 29 and 30 is reduced. Conversely, if the pressure in the chamber 43 decreases, the biasing force of the spring 38 displaces the driving rod in the direction away from the adjusting screw 36 thus increasing the retardation force acting on the advancing yarn 18. It is evident from the drawing that a positive connection between the diaphragm 42 and the driving rod 40 is established in the direction toward the adjusting screw 36 only, whereas the movement in the other direction is controlled by the spring 38 and is limited by the abutment of the disc 30 against I the disc 29, while the diaphragm 42 is permitted to continue its movement in this direction if the pressure drop in the pressure chamber 43 justifies the same.

The method for controlling the tension of an advancing yarn according to the invention utilizes the aforementioned apparatus in a manner which will now be described. The yarn 18 whose tension is to be controlled during the advancement of the same is inserted into the eyelet 23, between the retarding discs 29 and 30 and into the groove so as to rest against the abutments 9 and and the wall 6, and is further forwarded to yarn advancement means of a conventional design, which is not illustrated, in the direction indicated by arrows in FIGS. 1 and 3 which is also to be the direction of its subsequent advancement. However, this is not essential to the invention and, should a need arise, the direction of advancement and, consequently, the insertion procedure can be reversed. It is to be noted that this device can be adjusted to various thicknesses of the yarns by a simple exchange of the spacer 3 and by adjusting the adjustable screw 36 so that the tensioning force corresponds to a desirable value for the particular yarn.

Subsequently to adjusting the screw 36, an air stream emanating from the jet nozzle 11 is blown against the advancing yarn 18 so that the same comes to rest against the abutments 9 and 10 and deflects between the same as shown in FIG. 1, as a result of the positive pressure in the confined space defined by the plates 1 and 4, the spacer 3 and the advancing yarn 18 itself. It is evident that the degree of this deflection will be a function of the pressure of the medium blown through the jet nozzle 11 and the tension in the yarn l8. Consequently, if the yarn tension is constant, the deflection will increase with the increasing pressure of the supplied medium. However, the method according to the invention uses the other possibility, i.e., the pressurized medium pressure is adjusted to a level which assures an optimum reaction to the deviations from the selected tension force and kept at this constant level during the operation of the device, and the deflection of the yarn is then a function of the tensioning force in the yarn only. The positive pressure in the confined space, which is proportional to the deflection of the yarn, is conducted via the bore 14 and the conduit 15 into the pressure chamber 43, thus deflecting the diaphragm 42 so as to push the driving rod 40 against the biasing force of the spring 38 towardthe adjusting screw 36, thus reducing the retardation force exerted by the discs 29 and 30 on the advancing yarn 18. It is evident, that the larger the deflection of the yarn in the sensing means, i.e. the smaller the tension therein, the smaller is the positive pressure in the confined space and the pressure chamber 43 and the smaller is the reduction of the selected biasing force, i.e., the larger the retardation force exerted by the discs 29 and 30 on the advancing yarn 18, and, consequently, the tensioning force in the yarn.

As already mentioned, the pressure of the pressurized medium being supplied by the conduit 13 and the jet nozzle 11 into the confined space is adjustable, and this adjustment of the pressurized medium being supplied from a source is accomplished by a reducing valve, both the source and the valve being of a conventional design and not a part of the invention and consequently, not illustrated. If the device according to the invention is to be used in a textile machine, the pressurized medium is preferably supplied from a central pressurized medium source, such as an air compressor or the like, for all devices to be simultaneously used, and the pressure is adjusted by one central reducing valve for all such devices. If such is the case, only the biasing force of the springs 36 of all devices is adjusted to the same magnitude so as to assure the same tensioning forces for all yarns. As in case of only one device, the retardation force of all these devices can be adjusted by adjusting the pressure of the medium by the reducing valve.

Since the retardation force exerted on the advancing yarn 18 by the discs 29 and 30 is controlled by the pressure in the chamber 43 and thus in the confined space between the advancing yarn and the walls of the sensing means, and the deviation of the yarn between the abutments 9 and 10 is directly proportional to the pressure in the confined space, the magnitude of the deflection of the yarn as established by the markings 17 is an indication of the tension in the advancing yarn l8.

FIG. 5 shows a different embodiment of the pneumatic amplifier 16. The diaphragm 42' is supported in an electrically conductive mount 45 and is provided with a flexible contact strip 46 whose outer end is held by the mount 45' and whose inner end is attached to the diaphragm 42 by a rivet 47 or any other suitable electrically conductive attachment means. A bridging contact 48 is also attached to the diaphragm 42, preferably by the same rivet 47. The housing 41 of the amplifier 16 is of an electrically insulating material and two tenninals 49 and 50 of an electric indication circuit, comprising an electric source and a'conventional signal lamp or the like, establish a connection between the inside and the outside of the amplifier 16'. As the tension in the advancing yarn increases, the pressure in the confined space in front of the jet nozzle ill increases and so does the pressure in the chamber 43", and the diaphragm 42' is deflected toward the terminals 49 and 50. If the yarn tension exceeds a predetermined value, the bridging contact 48 establishes a connection between the terminals 49 and 50 thus activating the electric circuit, and the signal lamp lights up indicating an excessive tension in the yarn.

There are further provided two terminals 51 and 52 connecting the inside of the amplifier 41' with the outside thereof. An electric source and a relay controlling the drive of the advancing yarn are arranged in an electric circuit which is attached to these terminals, which circuit serves for detection of yarn breakage and for shutting off the drive if the same occurs. In case of yarn breakage, the air escaping through the jet nozzle 11 induces a negative pressure in the bore 14 which is transmitted by conduit l5 into the pressure chamber 43' thus deflecting the diaphragm 42 toward the terminal 52 and closing the above mentioned circuit so that the relay is activated shutting off the drive of the advancing yarn 18. When a new thread is inserted into the sensing means and properly tensioned, the pressure in the chamber 43 will rise and the contact between the rivet 47 and the terminal 42 is disconnected and the drive of the advancing meansis restarted.

It is evident, that even though the embodiment has been illustrated as comprising two independent circuits with two electric sources, it may be advantageous to have only one source whose one terminal is attached to the terminal 51 and wherein the circuits are established by contacting either the terminal 52 for the drive shutoff or one of the terminals 49 or 50 for excessive ten sion indication, the other terminal being superfluous.-

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions, differing from the types described above both within and without the textile industry.

While the invention has been illustrated and described as embodied in a textile machine, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. A method of controlling the tensioning force in an advancing yarn, comprising the steps of advancing the yarn under selected tension in a given path partly bounding a confined space; retarding said advancing yam with an adjustable force; sensing deviation from said selected tension in the advancing yam by directing a stream of pressurized medium in said confined space toward the advancing yarn so as to deflect said yarn in dependence upon the instantaneous magnitude of said yarn tension and simultaneously to obtain a pressure variation in said confined space as a function of said yarn deflection; and varying said adjustable force as a function of said pressure variation.

2. A method of controlling the tensioning force in an advancing yarn, comprising the steps of advancing the yarn under selected tension in a given path; retarding said advancing yarn with an adjustable force; sensing deviations from the selected tension in the advancing yarn; indicating a deviation from said selected tension above a first preselected limit; controlling the advancement of said yarn in dependence upon a deviation from said selected tension below a second preselected limit; and varying said adjustable force as a function of the sensed deviation from said selected tension above said second preselected limit.

3. In a device for controlling the tensioning force in advancing yarn which is to be maintained at a selected tension, a combination comprising first means for applying an adjustable retarding force to the advancing yarn including a stationary first retarding disc, a displaceable second disc, means for biasing said second disc toward said first disc with an adjustable force, and actuating means for displacing said second disc in relation to said first disc so as to apply an adjustable force to the advancing yarn passing between said first and second discs; second means for sensing variations from the selected tension in the advancing yarn including wall means defining with said advancing yarn a confined space and means for controlling said first means in dependence upon the sensed deviation so as to vary said adjustable force as a function of the same, and including a conduit communicating with said confined space for transmitting the instantaneous pressure therein to said actuating means for said second disc.

4. In a device for controlling the tensioning force in advancing yarn which is to be maintained at a selected tension, a combination comprising first means for applying an adjustable retarding force to the advancing yarn and including pneumatically activated actuating means; second means for sensing variations from the selected tension in the advancing yarn and including wall means defining with the advancing yarn a confined space and means for supplying pressurized medium into said confined space, and third means for controlling said first means in dependence upon the sensed deviation by transmitting the instantaneous pressure in said confined space to said actuating means to thereby vary said adjustable force of said first means as a function of time.

5. A combination as defined in claim 4, wherein said first means further comprises a stationary first retarding disc, a displaceable second disc, and means for biasing said second disc toward said first disc with an adjustable force, said actuating means being operative for displacing said second disc in relation to said first disc so as to apply an adjustable force to the advancing yarn passing between said first and second discs; and wherein said third means comprises a conduit communicating with said confined space and with said actuating means.

6. A combination as defined in claim 4, wherein said wall means comprises a support plate comprising two abutments for supporting the advancing yarn which is free to deflect between said abutments in dependence upon the instantaneous pressure in said confined space; a spacer; and a cover plate which is of transparent material and which is provided with markings indicating the value of the tension in the advancing yarn as a function of the deflection of the same.

7. A combination as defined in claim 4, comprising first additional means for generating a signal when the pressure in said confined space exceeds a first preselected limit, and second additional means for disconnecting said yarn advancement means when said pressure drops below a second preselected limit.

8. A combination as defined in claim 7, wherein said first additional means are electric contact means establishing contact between an electric source and an indication means, and wherein said second additional means are electric contact means establishing contact between the electric source and a relay controlling the drive for advancement of the yarn. 

1. A method of controlling the tensioning force in an advancing yarn, comprising the steps of advancing the yarn under selected tension in a given path partly bounding a confined space; retarding said advancing yarn with an adjustable force; sensing deviation from said selected tension in the advancing yarn by directing a stream of pressurized medium in said confined space toward the advancing yarn so as to deflect said yarn in dependence upon the instantaneous magnitude of said yarn tension and simultaneously to obtain a pressure variation in said confined space as a function of said yarn deflection; and varying said adjustable force as a function of said pressure variation.
 2. A method of controlling the tensioning force in an advancing yarn, comprising the steps of advancing the yarn under selected tension in a given path; retarding said advancing yarn with an adjustable force; sensing deviations from the selected tension in the advancing yarn; indicating a deviation from said selected tension above a first preselected limit; controlling the advancement of said yarn in dependence upon a deviation from said selected tension below a second preselected limit; and varying said adjustable force as a function of the sensed deviation from said selected tension above said second preselected limit.
 3. In a device for controlling the tensioning force in advancing yarn which is to be maintained at a selected tension, A combination comprising first means for applying an adjustable retarding force to the advancing yarn including a stationary first retarding disc, a displaceable second disc, means for biasing said second disc toward said first disc with an adjustable force, and actuating means for displacing said second disc in relation to said first disc so as to apply an adjustable force to the advancing yarn passing between said first and second discs; second means for sensing variations from the selected tension in the advancing yarn including wall means defining with said advancing yarn a confined space and means for controlling said first means in dependence upon the sensed deviation so as to vary said adjustable force as a function of the same, and including a conduit communicating with said confined space for transmitting the instantaneous pressure therein to said actuating means for said second disc.
 4. In a device for controlling the tensioning force in advancing yarn which is to be maintained at a selected tension, a combination comprising first means for applying an adjustable retarding force to the advancing yarn and including pneumatically activated actuating means; second means for sensing variations from the selected tension in the advancing yarn and including wall means defining with the advancing yarn a confined space and means for supplying pressurized medium into said confined space, and third means for controlling said first means in dependence upon the sensed deviation by transmitting the instantaneous pressure in said confined space to said actuating means to thereby vary said adjustable force of said first means as a function of time.
 5. A combination as defined in claim 4, wherein said first means further comprises a stationary first retarding disc, a displaceable second disc, and means for biasing said second disc toward said first disc with an adjustable force, said actuating means being operative for displacing said second disc in relation to said first disc so as to apply an adjustable force to the advancing yarn passing between said first and second discs; and wherein said third means comprises a conduit communicating with said confined space and with said actuating means.
 6. A combination as defined in claim 4, wherein said wall means comprises a support plate comprising two abutments for supporting the advancing yarn which is free to deflect between said abutments in dependence upon the instantaneous pressure in said confined space; a spacer; and a cover plate which is of transparent material and which is provided with markings indicating the value of the tension in the advancing yarn as a function of the deflection of the same.
 7. A combination as defined in claim 4, comprising first additional means for generating a signal when the pressure in said confined space exceeds a first preselected limit, and second additional means for disconnecting said yarn advancement means when said pressure drops below a second preselected limit.
 8. A combination as defined in claim 7, wherein said first additional means are electric contact means establishing contact between an electric source and an indication means, and wherein said second additional means are electric contact means establishing contact between the electric source and a relay controlling the drive for advancement of the yarn. 